Using Environment Variables

When you set environment variables, they are injected into the container and are accessible to your code. Environment variables are set as key/value pairs. For example, suppose you are running a service that enables additional logging when it reads LOGGING_VERBOSE: true in the environment. In this scenario, you set the environment variable key/value pair as LOGGING_VERBOSE=true. The exact commands or UI are shown in the following sections.

Caution: You should not use environment variables to store and consume secrets. Instead, use Secrets.

Reserved names

The environment variables defined in the container runtime contract are reserved and cannot be set. In particular, the PORT environment variable is injected inside your container by Cloud Run for Anthos on Google Cloud. You should not set it yourself.

Setting environment variables on a service

Any configuration change leads to the creation of a new revision. Subsequent revisions will also automatically get this configuration setting unless you make explicit updates to change it.

You can set environment variables using the Cloud Console, the gcloud command line, or a YAML file when you create a new service or deploy a new revision:

Console

1. Go to Cloud Run

2. Click Create Service if you are configuring a new service you are deploying to. If you are configuring an existing service, click on the service, then click Edit and Deploy New Revision.

3. Under Advanced Settings, click Variables.

   

4. Do the following:

   • If you are adding a variable, click Add Variable, and specify the name you want for the variable and its value in the Name and Value text boxes.
   • If you are changing a value for a variable, replace the current value in the Value text box with the one you want.
   • If you are removing one or more environment variables, hover your cursor to the left of the Value textbox of the variable you are removing to display the Trash icon, and click it.

5. Click Create or Deploy.

Command line

To set, update, or remove environment variables of an existing service, use the gcloud run services update command. You can use any of the following flags, as needed:

• --set-env-vars
• --update-env-vars
• --remove-env-vars
• --clear-env-vars

You can specify environment variables while deploying a service, or update them after the service is created:

gcloud run deploy [SERVICE] --image IMAGE_URL --update-env-vars KEY1=VALUE1,KEY2=VALUE2

gcloud run services update SERVICE --update-env-vars KEY1=VALUE1,KEY2=VALUE2

• Replace SERVICE with the name of your service.
• Replace KEY1=VALUE1,KEY2=VALUE2, with the comma separated list of desired variable names and their values.
• Replace IMAGE_URL with a reference to the container image, for example, gcr.io/myproject/my-image:latest.

If you have too many environment variables that cannot be easily listed in KEY1=VALUE1,KEY2=VALUE2 format, you can alternatively repeat the flags listed above multiple times:

 [...]
 --set-env-vars "KEY1=VALUE1" \
 --set-env-vars "KEY2=VALUE2" \
 --set-env-vars "KEY3=VALUE3"

Because the comma character , is used to split environment variables, if your environment variable contains comma characters as values, you need to escape those delimiters by specifying a different delimiter character, for example, @:

 --set-env-vars "^@^KEY1=value1,value2,value3@KEY2=..."

YAML

You can download and view existing service configuration using the gcloud run services describe --format export command, which yields cleaned results in YAML format. You can then modify the fields described below and upload the modified YAML using the gcloud beta run services replace command. Make sure you only modify fields as documented.

1. To view and download the configuration:

   gcloud run services describe SERVICE --format export > service.yaml

2. Update the name and value attributes under the env attribute under containers::

   apiVersion: serving.knative.dev/v1
   kind: Service
   metadata:
     name: SERVICE
   spec:
     template:
       spec:
         containers:
         - env:
           - name: KEY-1
             value: VALUE-1
           - name: KEY-N
             value: VALUE-N

   Replace

   • SERVICE with the name of your Cloud Run for Anthos service
   • KEY-1, VALUE-1 with the environment variable and value. Optionally add more variables and values as desired.

3. Replace the service with its new configuration using the following command:

   gcloud beta run services replace service.yaml

Setting default environment variables in the container

You can use the ENV statement in a Dockerfile to set default values for environment variables:

ENV KEY1=VALUE1,KEY2=VALUE2

Order of precedence: container vs service variables

If you set a default environment variable in the container and also set an environment variable with the same name on the Cloud Run for Anthos service, the value set on the service takes precedence.

Enabling Kubernetes service links in Cloud Run for Anthos

If you use Kubernetes service links in Cloud Run for Anthos and want to continue using them, you must manually enable support for that feature before January 2021. Due to the performance issues seen in namespaces with thousands of services and revisions, starting in January 2021, Kubernetes service links will be disabled by default.

Important: Information about each of your services are injected into your pod's environment variables when you enable Kubernetes service links. In namespaces that contain over 1,000 Cloud Run for Anthos services or revisions, you might experience performance issues or even service failures.

To enable Kubernetes service links, run the following command to set data.enable-service-links to true in your knative-serving/config-defaults ConfigMap:

kubectl patch cm -n knative-serving config-defaults -p '{"data":{"enable-service-links":"true"}}